The present invention relates to fluid displacement pumps, and more particularly to fluid displacement pumps which utilize a low-friction flexible partition within a rigid hollow body.
There are a great number and variety of pumps in the art. The typical purpose of a pump is to move air or liquid from one location or container to another. Generally, a piston is movable within the pump to create a negative pressure or vacuum which moves the fluid from one location to the other. Pumps can be manually actuated or connected to a mechanical device. One of the problems associated with prior art pumps is that they have typically produced a tremendous amount of friction between the piston and the cylinder in which the piston moves. This limits the efficiency of the pump and increases running costs.
Although the surfaces of the piston and cylinder can be lubricated, this is not acceptable in all applications. For example, in a nursing breast pump the extracted milk should be as pure as possible so as not to adversely affect the baby. Hand pumps which do not have lubricated pump surfaces exist, but they take longer to extract an adequate amount of milk due to the friction which must be overcome while pumping.
Therefore, what is needed is a pump which significantly reduces the friction between moving parts without the use of a lubricant. What is further needed is a pump which is capable of pumping greater volumes than existing pumps of comparable size. The present invention fulfills these needs and provides other related advantages.